Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA.
Sci Rep. 2019 Dec 27;9(1):20228. doi: 10.1038/s41598-019-56712-4.
The AAA + ATPase R2TP complex facilitates assembly of a number of ribonucleoprotein particles (RNPs). Although the architecture of R2TP is known, its molecular basis for acting upon multiple RNPs remains unknown. In yeast, the core subunit of the box C/D small nucleolar RNPs, Nop58p, is the target for R2TP function. In the recently observed U3 box C/D snoRNP as part of the 90 S small subunit processome, the unfolded regions of Nop58p are observed to form extensive interactions, suggesting a possible role of R2TP in stabilizing the unfolded region of Nop58p prior to its assembly. Here, we analyze the interaction between R2TP and a Maltose Binding Protein (MBP)-fused Nop58p by biophysical and yeast genetics methods. We present evidence that R2TP interacts largely with the unfolded termini of Nop58p. Our results suggest a general mechanism for R2TP to impart specificity by recognizing unfolded regions in its clients.
AAA+ATPase R2TP 复合物有助于组装许多核糖核蛋白颗粒 (RNPs)。尽管 R2TP 的结构已知，但它对多种 RNPs 作用的分子基础尚不清楚。在酵母中，框 C/D 小核仁 RNPs 的核心亚基 Nop58p 是 R2TP 作用的靶标。在最近观察到的 U3 框 C/D snoRNP 作为 90S 小亚基加工体的一部分中，观察到 Nop58p 的展开区域形成广泛的相互作用，表明 R2TP 在其组装之前可能在稳定 Nop58p 的展开区域方面发挥作用。在这里，我们通过生物物理和酵母遗传学方法分析了 R2TP 与麦芽糖结合蛋白 (MBP)融合的 Nop58p 之间的相互作用。我们提供的证据表明，R2TP 主要与 Nop58p 的展开末端相互作用。我们的结果表明，R2TP 通过识别其客户的展开区域来赋予特异性的一般机制。
